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Re: spark gap question



Hi Thomas,

	You have hit on a basic problem that may not be well understood.  The
reason you can't run a conventional Tesla coil from low voltages is due the
the primary inductance, current, and frequency.  Assuming a typical coil's
primary inductance is 50uH and the frequency is 200kHz and the peak current
is 400 amps, you can calculate the voltage needed across the primary coil.
The formula is:

V = 2 x pi x Fo * L * I

where:
V = is the peak voltage
pi = 3.14159...
L = is the inductance in Heneries
I = is the peak current

In this example, the voltage needed works out to 25133 volts!  If you had
only 300 volts across the coil, the current would drop to only 4.8 amps.
We use very high voltages to force very high currents in the primary
inductor.  In this case we would need a switch that can handle 25kV at 400
amps.  Sparks gaps are the only easy thing we can get or hands on to do
this.  

	Terry



>
>Original Poster: Thomas Helwig 
>
>Hello all
>I would like to pose this question for consideration.  It seems to me, from
>many posts, that spark gaps consume a lot of energy and seem to be
>problematic in general.  What if you could get approximately 208 volts up
>to300 amps or 115 volts up to 500amps supply at any frequency you desire?
>Would this eliminate the necessity for the spark gap?
>